1. Field of the Invention
The invention relates to a shaver blade for arthroscopic and endoscopic use comprising an elongated inner tubular member rotatable within an elongated outer tubular member. In particular, the invention relates an elongated end-cutting shaver blade for resecting tissue presented perpendicular to the axis of the device.
2. Description of the Prior Art
The use of elongated surgical cutting or resection instruments has become well accepted in performing closed surgery such as arthroscopic or, more generally, endoscopic surgery. In closed surgery, access to the surgical site is gained via one or more portals, and instruments used in the surgical procedure must be elongated to permit the distal ends of the instruments to reach the surgical site. Surgical cutting instruments for use in closed surgeryxe2x80x94also known as xe2x80x9cshaversxe2x80x9dxe2x80x94conventionally have a straight, elongated outer tubular member terminating at a distal end having an opening in the end or side wall (or both) to form a cutting port or window and a straight, elongated inner tubular member concentrically disposed in the outer tubular member and having a distal end disposed adjacent the opening in the distal end of the outer tubular member. The distal end of the inner tubular member also has a window opening having a surface or edge for engaging tissue via the opening in the outer tubular member and in many cases (but not all) cooperates with the outer opening to shear, cut or trim tissue. In some cases, such as burrs, the opening in the outer tube merely allows access to the tissue and does not otherwise cooperate with the inner window. The inner tubular member is rotatably driven about its axis from its proximal end, normally via a handpiece having a small electric motor which is controlled by finger actuated switches on the handpiece, a foot switch or switches on a console supplying power to the handpiece. The distal end of the inner tubular member can have various configurations depending upon the surgical procedure to be performed, and the opening in the distal end of the outer tubular member has a configuration to cooperate with the particular configuration of the distal end of the inner tubular member. The various configurations and combinations of inner and outer members produce assemblies, the individual and combined components of which are referred to generically as shaver blades or cutting blades. Resected tissue is aspirated through the hollow lumen of the inner tubular member to be collected via a vacuum tube communicating with the handpiece.
The aforementioned elongated surgical cutting instruments have also been produced in angled configurations in which the distal tips of the inner and outer members are aligned and offset or bent at either a fixed or variable angle from the proximal ends of the aligned inner and outer members. Examples of fixed and variable angle rotary surgical instruments are shown in U.S. Pat. No. 4,646,738 (Trott) and U.S. Pat. No. 5,411,514 (Fucci et al.), both assigned to the assignee hereof, and incorporated by reference herein. In other respects the operation of fixed and variable angle shavers is largely the same as that of the straight shavers described above.
Shaver blades are usually optimized for a particular surgical procedure or part thereof. Thus, during a procedure a surgeon may use shaver blades optimized for cutting various types of tissue. Certain tissue, because of its particular anatomical position is best resected by a shaver blade designed for such tissue. Thus, end-cutting shaver blades are used for certain applications where the tissue to be resected is in line with the axis of the blade, or nearly in line. That is, the inner and outer windows are so aligned that tissue situated in a plane perpendicular to the blade axis may be introduced to the windows and resected. The invention relates to improvements in end-cutting shaver blades. It has been found that meniscal tissue may be particularly efficiently resected with the invention described herein.
It is accordingly an object of this invention to produce a rotating shaver blade capable of use as an end cutter.
It is also an object of this invention to produce a rotating end-cutting shaver blade particularly suited for resecting meniscus tissue.
It is a further object of this invention to produce a shaver blade having an end-facing cutting window to facilitate introduction of tissue endwise into the window.
These and other objects of this invention are achieved by the preferred embodiment disclosed herein which is a surgical tissue resecting instrument comprising elongated inner and outer cylindrical members adapted for relative movement. The cylindrical wall at the distal end of the outer tubular member is provided with at least two notches, each notch having a proximally situated apex and a distally facing notch opening. Each notch further comprises longitudinally extending sides between its apex and opening, each side having a cutting edge lying on the inner circumferential surface of the outer member. The cylindrical wall at the distal end of the inner tubular member is also provided with at least two notches, each having a proximally situated apex and a distally facing notch opening. Each notch further comprises longitudinally extending sides between its apex and its opening, each side having a cutting edge lying on the outer circumferential surface of the inner member. Relative rotation of the inner and outer members will resect tissue presented at the notch openings.